Technical Field
The present invention concerns a synchronous generator of a gearless wind power installation. The application also concerns a wind power installation having such a generator. Furthermore the present application concerns a transport arrangement for transporting a synchronous generator of a gearless wind power installation.
Description of the Related Art
Wind power installations, in particular horizontal-axis wind power installations, of which one is shown in FIG. 1, are generally known. In the case of a gearless wind power installation as shown in FIG. 1 an aerodynamic rotor directly drives the rotor of a generator so that the generator converts the kinetic energy obtained from the wind into electric energy. Therefore the rotor of the generator rotates as slowly as the aerodynamic rotor. To take account of such a slow speed of rotation the generator is of a generator diameter which is comparatively large in relation to the nominal power, in particular being of a large air gap diameter. In that way, in spite of the slow speed of rotation, it is possible to achieve a comparatively high differential speed between generator rotor and stator in the region of the air gap. Modern wind power installations such as for example an E126 from ENERCON GmbH has a nominal power of 7.5 MW. The E126 is also a gearless wind power installation and requires a generator which is also correspondingly large from the point of view of structural size.
A problem in that respect is in particular that of transporting such a generator to an erection location for the wind power installation. In many countries the maximum width which can be transported on the road is about 5 m. That means that the maximum diameter of the generator may be 5 m in transport when the generator is transported in a lying position, that is to say with an axis of rotation perpendicular to the road. The diameter of a generator is thereby de facto limited. Even if such a transport problem could be resolved for many erection locations, in particular those in the proximity of a generator manufacturer or in the proximity of a port, nonetheless a standard generator which is the aim to achieve and which is frequently to be used is limited by that transportation dimension.
The specified wind power installation of type E126 has a generator with an air gap diameter of about 10 m. With that generator the transport problem is resolved by the generator being transported in several parts, more specifically by the generator rotor and stator each being subdivided into four parts. The rotor and stator are thus delivered in individual parts and assembled on the building site or in the proximity thereof.
A problem in that respect is that such separated parts have to be re-assembled on site and thus outside of the generator manufacturing facilities. It is complicated and expensive and susceptible to defects. Checking of the assembly or checking of the finished generator is also more difficult on site and thus more complicated and expensive and also more susceptible to defect, than at the location where the generator is manufactured.
Thus it is known for example from other wind power installations from ENERCON GmbH that a continuous winding for the stator can be advantageous. That is described for example in European patent EP 1 419 315 B1. The winding described therein of the stator is very complicated and expensive and basically can only be reliably implemented in the factory premises. It will be noted however that the result is a generator which is highly reliable in operation. A continuous winding which is implemented in the factory premises in that respect excludes separation into a plurality of parts for transport purposes.
The German Patent and Trade Mark Office searched the following state of the art in the priority application: DE 199 23 925 A1, US 2010/0024311 A1, DE 10 2009 032 885 A1, and DE 10 2010 039 590 A1.